Clinical Utility of Cardiovascular Magnetic Resonance in Hypertrophic Cardiomyopathy

The unique capability of contrast-enhanced CMR with late gadolinium enhancement to identify myocardial fibrosis has raised the expectation that this may represent a novel marker, which may enhance risk stratification. At this time, late gadolinium enhancement appears to be an important determinant of adverse LV remodeling associated with systolic dysfunction. However, the predictive significance of LGE for sudden death is incompletely resolved and ultimately future large prospective studies may provide greater insights into this issue. These observations underscore an important role for CMR in the contemporary assessment of patients with HCM, providing important information impacting diagnosis and clinical management strategies.Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiomyopathy (prevalence of 1:500 in the general population) caused by mutations in genes encoding proteins of the cardiac sarcomere [1-5]. A clinical diagnosis of HCM is confirmed when unexplained increased LV wall thickness is imaged (range 13-60 mm with average 22 mm) in the presence of a nondilated LV chamber [1,3,6]. HCM is a global disease affecting many races and equally by gender [7,8]. Despite a diverse pattern of phenotypic expression and clinical course, HCM is compatible with normal life expectancy in the vast majority of patients [9-11]. However, a small but important subset of HCM patients remain at increased risk of adverse disease complications such as sudden death, progressive heart failure symptoms or stroke [1,12-15].Genetics. HCM is caused by vast genetic heterogeneity with > 1,400 mutations in 13 or more genes encoding contractile proteins of the cardiac sarcomere (or in sarcomere-associated proteins) with cardiac β-myosin heavy chain (MYH7) and cardiac myosin binding protein C (MYBPC3)(Figure 1) the two most common sarcomere mutant genes, each accounting for the majority of HCM [5,16-18]. Mutations responsible for HCM are transmitted in an autosomal dominant